Air-filter drive



E. SZEKELY Aug. 9 1927.

AIR FILTER DRIVE Filed Sept. 20. 1926 [72 4 672K5 2? 77265? zakefy 5M1 2726" .5565: v 5 m 140 411. 4, 8%

Patented Aug. 9, 1927.

UNITED STATES 1 PATENT OFFICE.

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Application fled leptelber M, 1m I0. mm.

This invention relates to improvements in air filters and the like, andmore particular- 1 to improved means for controlling the d riving mechanism of such filters as the movin belt type, wherein a metallic foraniinous It is mounted on sprockets and extends across the air stream, with the lower end of the belt immersed in an oil bath for cleaning the belt, removing the dust, and re-oiling the surfaces.

In such air washing apparatus it is found that the newly cleansed belt is inefficient, and that the highest efliciency is obtained by leaving the belt in the air stream until the belt is well coated with dust. Accordingly, a slow, intermittently operating drive is 511' plied, which moves the belt, for examp e one-sixth of the length at each operation. The result is that a newly cleansed portion of the belt is in the air stream at one side, and the portion which has been in the stream the longest is directly opposite. The e riods in which the portions on the one side have been in the air stream increase as the periods of the portions directly opposite decrease, with the result that an even effect is obtained throughout the air channel.

Heretofore, drives controlled by clockwork timing devices and intermittent gearing have been used. The belt was moved at fixed time intervals and obviously no allowance was made for changes in the amount of air drawn through the filter.

The main objects of this invention are to provide a more simple and reliable method of moving the screen, and to provide such means controlled directly b the air stream so that the screen is move more nearly in proportion to the amount of air which is passed through.

An illustrative embodiment of this invention is shown in the accompanying drawings in which Figure 1 is an elevation of the air cleaning system.

Fig. 2 is an end elevation of the reduction gear housing and cam with a diagram of the electrical connections.

In the drawings, the air is drawn through the filter unit 1 by means of the rotary blower 2, driven by the motor 3.

The filter unit comprises a housing 4 in ter screen 7 which comprises an endleforaminous metallic belt.

Mounted on the outer end of the upper shaft 5 is a worm wheel 8 which with a-worm 9, secured 'on the end of the screen 00 driving motor 10. The motor is 0 rated a sufficient length of time to turn belt wheel 6 approximately one-half a revolution and then stop.

The housing 4 is apertured at either side, the. one aperture 11 being for admitting air, and the other aperture bein connected to the intake of the blower 2. e aperture 11 is preferably reduced to circular form to confine the air stream to the circle of the screen motor controlling fan 12, which is mounted in the housin of the speed reduction unit 13, su portet? on the frame14.

The speed re uction unit 13 may be of any well known type suitable for effecting a very large reduction from the fan shaft 15 to the cam shaft 16, mounted on the opposite side of the housing and positively connected to the shaft 15.

A switch lever 17 is centrally pivoted on the housing of the reduction unit 13, and carries a mercury bulb screen motor switch 18 on the outer end, while the inner end 19 bears against the surface of the cam 20, secured on the shaft 16. The cam 20 has a lobe 21 which, at each revolution of the cam 20, contacts with the end 19 of the switch lever 17 and closes the normally open switch 18 for a short are of movement of the cam.

The switch 18 controls the screen motor 10: as shown in Fig. 2 the switch 18 is connected in series with the motor 10 to the sup 1y lines A through the main hand contro ed switch 22. The supply motor 3 is also connected behind the main switch 22.

In the construction described, the fan 12 is operated whenever the supply fan 2 is running, and the speed of the fan 12 is proportional to the amount of air drawn through the filter 1. Intermittently the 100 screen motor switch is operated to turn a new section of the filter screen 7 into the air stream and then 0 ened when the lobe 4 moves away from t e lever end 19. I

If the supply motor 3 is shut off while the 108 lobe 21 is on the end of the lever 17, the screen motor is also stopped because the two motors are both behind the main switch. Otherwise, the screen motor would continue to run until the air stream was re-started; 110

but, with the above provision made, the movement of the screen is stopped until the filter is again started, then the movement ofthe screen is completed. While but one specific embodiment of this invention has been. herein shown and described, it will be understood that numerous details of the construction shown mag be altered or omitted without de artinig' om the spirit of this invention as efine by the following claims.

I claim:

1 In an air filter, a movably mounted filter screen, a motor for moving said screen, a fan mounted in the path of the air passin through said screen and driven thereby,

an a switch for said motor controlled by the fan.

2. In an air filter a movably mounted filter screen, a motor or movin 'said screen, a fan mounted in the path of t e air passing through said screen and driven thereby, a switch for said motor, and means ositively operated by said fan for contro 'ng said \5 switch.

3. In an air filter, a movably mounted filter screen, a motor for moving said screen,

a fan mounted in the path of the air passing through said screen and driven thereby, a switch for said motor, and a cam itivel operated by the fan for contro 'ng sai switch.

4. In an air filter, a movabl mounted screen, a motor for moving sai screen, a fan operated by the air currents passing through said screen, and means positively operated by said fan for intermittently operating said motor.

5. Inan air filter, a movabl mounted screen, a motor for moving sai screen, a fan operated by the air currents passing through said screen, a ca-m'positively driven by said fan, said cam havin a lobe, and a motor switch operated by said lobe.

6. In an air filter, a movably mounted screen, a motor for moving said screen, a fan operated by the air currents passing throu h said screen, a cam positively driven by said fan and a motor switch intermittently operated by said cam.

Signed at Chicago this 10th day of September, 1926.

ERNEST szEKELY. 

